Technical Field
Embodiments of the present disclosure are directed to charge pump overload detection circuits and devices including a charge pump overload detection circuit.
Description of the Related Art
Charge pumps are a kind of DC to DC converter that are used to convert input DC power to an output DC power at a different voltage level. Charge pumps are utilized in a wide variety of electronic circuits and devices, including, for example, ranging devices (such as a time of flight imaging sensor) or proximity sensors.
In a time of flight imaging device, a charge pump may be included to provide a biasing voltage to reverse bias an array of single photon avalanche diodes (SPADs) such that a single photon incident on any SPAD in the array is detectable, as that photon will cause an avalanche which may be detected as an output pulse. However, in relatively high light conditions, many or all of the SPADs in the array may be in an avalanche condition at the same or substantially same time, thus presenting an increased load on the charge pump as the SPADs draw an increased charge from the charge pump. The output voltage of the charge pump thus begins to decrease, which reduces the SPAD sensitivity to incident photons and may result in an incorrect count rate (i.e., a count of incident photons) or other device malfunctions.